OBJECTIVES: 1. Enzymatic changes during the adipose conversion of 3T3-L1; 2. Serum factors in relation to the adipose conversion; 3. Fibroblast factors in the support of keratinocyte multiplication; 4. Comparison of the phenotypes of cultured cells derived from different stratified squamous epithelia; 5. Relation of protein synthesis and transglutaminase activity to formation of the cross-linked envelope during terminal differentiation of the cultured human epidermal keratinocyte; 6. Synthesis of keratins by cultured epidermal cells; 7. Immunofluorescent staining of keratin fibers in cultured cells; 8. Relation between the different keratins of epidermal cells; 9. Development of the epidermal keratinocyte from primitive epithelium.